Introducing WireCat, a GHC plugin for writing typed categorical wiring diagrams with proc notation
Juan Raphael Diaz Simões
Senior Backend / Platform Engineer
I am a backend and platform engineer with ten years of experience and a PhD in complex systems science. I build and repair production systems where reliability, performance, and correctness matter: distributed infrastructure, observability and instrumentation, developer tooling, and data-intensive applications.
Available for senior engineering roles and consulting in platform architecture, reliability, performance, and observability.
Working remotely across EU and US teams for a decade. Tell me what you are building.
Selected Experience
Tlon — Owned fleet health and the control backend architecture of a hosting platform for Urbit pods running across multiple clusters: automated updates, fleet sizing, and memory optimization. The automation cut fleet costs tenfold; the observability work cut failure diagnosis from hours to a single trace lookup.
Tweag — Led a six-engineer consulting team, delivered infrastructure and regulated-system integrations, and made a production trading system up to 100× faster while reducing its memory use by an order of magnitude.
Research Background
PhD in Complex Systems Science from Paris-Saclay University. Developed LineageFlow, software for computational analysis of embryonic development. Published in Physical Biology and conference proceedings.
Selected Writing
Generalized effective numbers and entropies
December 16, 2025Working notes on generalized effective numbers, Hill numbers, and related entropies.
Summarizing multicore usage using entropy
January 2, 2023Python script using entropy and effective numbers to display multicore CPU usage in status bars
Arrows, through a different lens
April 15, 2021Using profunctor optics with Arrow-based workflows for better composability
Code is engineering, types are science
March 5, 2020Exploring deduction, induction, and abduction in software development through Peirce’s theory